Differential Diagnosis for Itching

The patient's complaint of itching can be caused by a variety of conditions. Here's a differential diagnosis organized into categories:

• Single Most Likely Diagnosis
  • Atopic Dermatitis (Eczema): This is a common condition characterized by dry, itchy skin. It's often seen in individuals with a history of allergies or asthma, and it can be triggered by various factors including soaps, detergents, or environmental allergens.
• Other Likely Diagnoses
  • Allergic Contact Dermatitis: This condition occurs when the skin comes into contact with an allergen, leading to an immune response that causes itching, redness, and blistering.
  • Psoriasis: An autoimmune condition that speeds up the life cycle of skin cells, causing cells to build up rapidly on the surface of the skin. The extra skin cells form scales and red patches that itch or burn.
  • Dry Skin (Xerosis): Often caused by environmental factors like cold weather, dry air, or excessive bathing, leading to itching and discomfort.
• Do Not Miss Diagnoses
  • Hypothyroidism: Although less common, hypothyroidism can cause dry skin and itching due to the decreased production of thyroid hormones, which are essential for skin health.
  • Lymphoma: Certain types of lymphoma, like cutaneous T-cell lymphoma, can present with itching as a primary symptom, often without any visible skin lesions.
  • Cholestasis: Itching can be a symptom of liver disease, particularly cholestasis, where bile flow is reduced or blocked, leading to the accumulation of bile salts in the skin.
• Rare Diagnoses
  • Polycythemia Vera: A rare blood disorder that can cause itching, particularly after warm baths or showers, due to the release of histamine from basophils.
  • Neurological Disorders: Certain neurological conditions, such as multiple sclerosis or neuropathy, can cause itching sensations without any visible skin changes.
  • Parasitic Infestations: Infestations like scabies or lice can cause severe itching, especially at night, and are often accompanied by visible skin lesions or burrows.